Dry concentrator.



,PATENTED JUNE 23, 1908.

H. P. CURTIS. DRY G ONUENTRATOR. APPLICATION FILED MAY 27, 1907.

2 SHEETSSHEET l.

O 0. 0 O Q m Irv w ,409. PATENTED JUNE 23, 1908.

H. P. CURTIS.

DRY GONGENTRATOR.

APPLICATION IE'ILBD MAY 27, 1907.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

HOMER P. CURTIS, OF DENVER, COLORADO, ASSIGNOR TO THE CURTIS DRY PLACER j MACHINE COMPANY, OF DENVER, COLORADO.

To all whom it may concern:

Bo it known that I, HOMER P. CURTIS, a citizen of the United States, residing in the city and county of Denver and State of Colorado, have invented certain new and useful Improvements in Dry Concentrators; and I do declare the following to be a full, clear, and exact descri tion of the invention, such as will enable ot ers skilled in the art to which it appertains to make and use the same, reference being had to the accom anying drawings, and to the letters and gures of reference marked thereon, which form a part of this specification.

My invention relates to improvements inap aratus for separating the precious metal va ues from the gangue, being more especially intended for use in treating placer material containing free recious metal values.

A distinguishing eature of my improved machine or apparatus is that the material is treated in a dry state thus obviating the necessity for making provision for a water supply which in many placer districts is very difficult to obtain.

My improved a paratus may be operated by hand when in t eform of a small machine,

both for the purpose ,of giving it the neceswith an intervening layer of mesh material preferably wire cloth. These two plates are provided with openings which are partially .out of alinement, whereby the spaces be tween the openings in the lower plate, ar-

- tially close the openings in the upper p ate in the bottom,-thus forming pockets or rece tacles for the saving of the precious metal va ues. Below this chute is arranged a tight air box into which the air blast is delivered from'a suitable blower, air com-' pressor or other source of supply.

The air blast enters the opening of the lower plate of the-chute bottom, and passes up through the mesh material and into the Specification of Letters Patent.

Application filed May 27, 1907. Serial No. 375,848.

close through the chute.

Patented June 23, 1908.

openings of the upper plate entering the same above the closed portions of the open ing, whereby the air under pressure sup orts the lighter material or gangue, and a lows the precious metal values to settle in the pockets of the upper late or the portions of the o enings in sa1d late whose bottoms are 5 by the lower p ate. The gangue being supported by the an, passes along down the bottom of the chute which is suitably inclined therefor and is finally discharged at its lower end. The pockets in the bottom of the chute are preferably so arranged that the opening for the entrance of the air from below varies. That is to say these pockets are arranged in series, the uppermost pockets of any series having larger spaces for the admission of air while the air spaces for the lower pockets of the series diminish in size, the lowermost pockets of the series having the smaller spaces for the admission of air.

The bottom of the chute may have any de sired number 'of these series of pockets.

When the device is in use, the material is fed to the upper extremity thereof and the chute is of sufhcient length to catch all of the precious metal values. For instance the uppermost pockets will catch a portion of these values and what escapes from these pockets will be caught in the other pockets as the material continues its downward movement It is assumed that the heavier particles will be caught in the uppermost pockets and that the finer values will accumulate in the other pockets. The air blast is introduced at the upper portion of the air box and the precious metal values accumulate in the various pockets as the material works downwardly through the chute, the gan ue being lighter is su ported by the blast while the precious meta values which are heavier or of greater specific gravity, pass downwardly into the pockets of the upper plate, accumulating therein forward 0 the upper spaces throughwhich the air enters the said ockets. The forward walls of the openings 1n the upper plate are undercut or downwardly inclined thus forming protected receptacles or pockets for the preclous metal values.

An oscillatory or vibratory movement is imparted to the chute, whereby the separation of the precious metal values from the gangue is facilitated.

Having briefly outlined my improved conrights 10 andlongitudinal to forming a rigid frame work w 'ch is trun-' nioned on the upright members 6, 7 and 8. This frame is provided with a centrally struction, the general manner of its operation and the function it is intended to perform, I will proceed to describe the same in detail reference being had to the accompanying drawin in which is illustrated an .embodimentt ereof.

In this' drawing, Figure 1 is a top plan view of my improved machine. Fig. 2 is a vertical longitudinal section of the same. Fig. 3 is an endelevation of the machine looking in the direction of arrow A in Fig. 1.

Fig. 4 is an enlarged fragmentar section of the bottom of the concentrating c ute. Fig. 5 is a top view of a portion of the chute bottom, illustrating an opening for a screw whereby the two lates of'the chute bottom are connected. ig. 6 is a sectional view of 'the same. Fig. 7 is a fragmentary detail sectional view of a portion of the concentrating chute. This section is taken on the line 77 Fig. 1, the parts, however, being shown on a larger scale.

The same reference characters indicate the same parts in all the views. 7

Let the numeral 5 designate a suitable stationary frame provided with upright members 6, 7 and 8 upon which the concentrating apparatus is ad uStably hung whereby any desired inclination of the concentrating chute or dry sluice may be obtained. This concentrating ap aratus consistsof a rectangular bottom flame 9 provided with upbeams 12,

located transversely disposed upper bar 13 which is rigidly connected at one extremity with one of the frame bars 12, while its outer extremity is formed into a journal or trunnion 14 engaging a box 15 at the top of the upright 8. t the opposite side from the trunnion-'14, the-frame work of the concentrator is trunnioned on an operating shaft 16 which is journaled in a gear case 17 secured to one of-the frame bars 12 by fastening devices 18. Upon the shaft 16 is made -fast a beveled gear 19 which meshes with a pinion 20 fast on a shaft 21 whose outer extremities are provided with crank wheels 22. -.The shaft 21 is journaled in the gear case at 23 while its outer extremities are 'ournaled in boxes 24 mounted on one o the frame bars 12.

Between the upper frame bars 12but raised considerably above the same, is the concentrating chute or dry sluice 25 provided -with a bottom-composed of an upper plate 26, a lower plate 27 and an interposed or intervening layer ofmesh material 28. The

height to give the chute or sluice the desired or necessary capacity. The upper plate 26 upper plate is provided with upwardly prois provided with openings 31 whose forward portions 32 constitute pockets closed at the ottom by the bottom plate 27 which is also provided with passages designated 34 which communicate with the rear openings 31 of'the upper p ate.

posed layer of mesh material preferably wire cloth, While of sufficient fineness to support the material within the upper portions 35 of the upper plate, at the same time are sufliciently open for the passage of the necessary air'blast for the treatment of the material.

As heretofore explained it is preferred that the openings 31 of the upper late and the corresponding passages 34 oft e lower plate be arranged in series. It may be assumed that one of these series is illustrated in Fig. 4 where the air space A communicating with the uppermost o ening 31, is widest, while the air space B next elow is somewhat narrower; while the air spaces C and D lower down diminish in width.

The two plates 26 and 27 and the intervening layer 28 of mesh material, may be connected in any suitable manner. It is highly desirable, however, if not absolutely necessary, that these members be connected in such a manner that they will be readily detachable for cleaning up purposes. As illustrated in the drawings these three members 26, 28 and 27 are connected by screws 36 which pass through slots 37 formed in the plate 26, the said screws being threaded in o enings formed in the bottom plate 27. The forward extremities of the slots 37 are enlarged as shown at 38, to ermit the heads of the screws to pass throug Hence when it is desired to disconnect the plates 26 and 27, it is only necessary to loosen the screws 36, and slide the plate 26 rearwardly until, the heads of the screws register with the enlarged opening 38, in which event the bottom plate 27 will fall downwardly in to the air box 39 below. I p

The plate 26 is provided with side flanges 40 while the air box has engaging corresponding flanges 41. These two sets of flanges are slotted as shown at 42 and 43 to receive bolts 44 whose lower extremities are threaded to receive nuts 45. To the upper extremities of these bolts are pivoted cam levers 46 which when thrown to the upright position shownin Fig. 7, look the plate 26 and the air box tightly together. After, however, the screws 36 connecting the members of the chute or dry sluice as heretofore explained, are disconnected by loosening the screws 36, and allowing the plate 33 to drop downwardly into the air box, the plate 26 may be detached from the air box by throwing the cam levers 46 to the flange members of the air box and plate.

ortions 35 of the The inter- I 3 cleaned.

The plate 26 will then be entirely free and may be shaken to cause any remaining values within the pockets to drop into the air box. The layer 28 of mesh material will also be This material may then be moved downwardly into the lower part 47 of the air box which isprovided with a door 48 hinged at 49. This door is locked in place by means of a hinged member 50 in which is threaded a bolt 51 its inner extremity bearing against the door 48. The extremity of the member 50 remote from the hinge passes through a U-shaped clip 52 hinged to the air box at 53. When this member 50 is in engagement with the loop 53, it isevident that the hinged door 48 may be held tightly in place. However, when it is desired to remove the concentrates or values from the air box, the screw 51 is loosened sufficiently to allow the clip 52 to be disconnected from thel'member 50 when the said member together with the door 48 are free to swing. upon the hinge pin 49, allowing the c'ontents of the air box to drop into a receptacle 54.

The rear extremity of the airbox is rovided with an elongated port 55 below W ich is located a nipple 56-jhaving an o ening 57. To this nipple is attached a suitab e conduit 58 which may be connected with any suitable source of air supply, for delivering the necessary air blast to the box 39.

- The concentrating frame work, trunnioned on the uprights 6, 7 and 8 as heretofore explained, 1S longitudinally tiltable by loosening a bolt 58 fast on one of the lower side bars 9" of the frame 9, and passing through a slotted bracket 59 fast on one of the standards 8. By loosening this bolt or a number of bolts (not shown) in case it is necessary to employ more than one, the entire frame work 9 upon which the concentrating chute or dry sluice is mounted, may be turned longitudinally on its trunnions to give any desired inclination to the chute, after which the said frame work is rigidly locked in place upon the standards. Hence this frame work 9 has no other movement. The concentrating chute, however, together with the air box 39, is mounted at each end upon a pair of links 60', whereby the said apparatus is free to oscillate transversely, and for this purpose pitmen 61 are connected at their outer extremities with the crank wheels 22 as shown at 62, the said con nection being of such a nature that the length of stroke may be varied as desired, and for this purpose'the crank wheels are rovided with dove-tailed grooves 22 in whic is slidably mounted a suitable device 63 for connecting each pitman with its corresponding crank wheel.

Now when the apparatus is in use, the material to be treated after being properly screened in any suitable manner, is discharged into the concentrating chute or dry sluice, the latter being simultaneously operconnecting t ated by imparting'a transverse oscillation thereto'through the instrumentality of the shaft 16, the gears 19 and 20, the shaft 21, the crank wheels 22 and the pitmen 61. At the same time a suitable air blast is introducedto the air box 39 through the port 55. This air under ressure passes upthrough the openings 34 of the bottom plate 33 of the chute, and thence through the mesh covered air spaces A, B and G into the various openings 31 of the upper plate of the said chute in the rear of the pockets 32. Y

The gangue or lighter material being supported by the air blast, passes downward y over the pockets, being eventually discharged from the lower end of the chute, while the precious metal values, which are too heavy to be removed by the air blast, move downward-1y and occupy the pockets 32, forward of the screened air spaces, as heretofore explained. The action of the air together with the lateral oscillation imparted to the concentrating apparatus, serves to produce the desired separation of the values from the gangue as heretofore outlined.

After the ap aratus has been operated a sufiicient length up, the oscillatory movement "of the concentrating apparatus is stopped as well as the delivery of the air to the air box. The screws 36 are then loosened, and the cam levers 46 actuated to release the chute from the air box. The up er plate is then moved of time to require cleaning rearwardly sufficient y to bring the heads of the screws 36 into alinement with the or tions 38 of the slots 37, which allows the ottom plate 33 to drop into the air box together with the mesh member 28, allowing the contents of the pockets. 32 to drop-into said box. These concentrates may then be removed from the lower extremity of the box as heretofore explained.

To the bottom of the air box is applied a transversely located channel bar 65 ada ted to straddle the stationary bar 13, and form an additional support for the air box and chute, to prevent the tendency of the said mechanism to swing downwardly which would interfere with the proper working of the supporting end links 60. The connection between the channel bar 65 and the sta- \tionary bar 13, is such'as to allow the oscillatory structure to move in an arc whose center is the lower pivots of the links, without disc said parts 65 and 13. Hence when the oscillatory structure is in the central position, there will be a narrow space between the top of the bar 13 and the bottom of the channel bar 65 (see Fig. 2).

It is referred to have recesses 66 formed in the ower plate 33 of the concentrating chute, between the pockets 32 of the u per plate and the passages 34 of the lower p ate, to receive any fine precious metal values which may follow the mesh material 28 forwardly between the upper and lower plates. Without this provision in case the metal values are very fine, they might after having once been caught, enter an opening 34 and be carried upwardly with the gangue especially if the opening 34 was one of the foremost openings of the chute.

It must be understood that I do not limit the invention to a chute having air spaces A, B, C etc., of varying width, though under some circumstances this form of construction is preferred for the reason that the greater air volume entering one pocket, may be sufficient to carry very light flake gold upwardl out of the pocket, and if so the lesser air vo ume of the forward pocket, would allow the same to settle in the pocket.

Having thus described my invention, what I claim is:

1. A dry concentrating chute or sluice Whose bottom is provided with aseries of pockets whose rear portions are open at the bottom to permit the introduction of an air blast from below, the rear portions of the pockets being also open to permit the escape of the air, substantially as described.

2. A concentrating chute or sluice whose bottom is composed of two lates having openings, and an interposed ayer' of mesh material, the plates being arranged so that the forward portions of the openings of the upper plate are covered at the bottom to form pockets, the openings in the rear of these pockets being exposed at the bottom to 35 allow an air blast to pass through the mesh material into the said pockets for the purpose set forth. I

3. A chute for dry concentration having a bottom provided with pockets whose bottomshave mesh covered rearportions for the admission of air under pressure, the forward portions of the pockets being closed and their rear portions open for the escape of the air, in combination with means for introducing air to the said pockets, and means for im- ..parting a. transverse oscillation to the chute for the purpose set forth.-

4. In dry concentrating apparatus, the

- combination of a sluice having a bottom pro- 50 vided with pockets whose rear portions are 0 en to permit the introduction of an air b ast, the rear portions of the pockets being also open to permit the escape of the air.

5 'A chute for dry concentration, comprising upper and lower plates and an interposed layer of mesh material, the said plate having openings, the forward portions of the openings of the upper plate being closed at the bottom by the lower plate to form pockets while the rear portions of these pockets are exposed at the bottom to permit the passage of air entering the openings of the lower 7 late, the two plates and the interposed mesh ayer being readily detachable for the purpose set forth.

a 6. In a dry concentrator, the combination with a suitable stationary frame work, of an auxiliary frame work trunnioned on'the stationary frame work, means for adjusting the inclination of the trunnioned frame work, and a concentrating chute mounted on the trunnioned frame work to permit the oscillatory movement, the said chute having pockets whose forward portions are closed at the bottom and whose rear portions are open at the bottom, and means for introducing air under pressure from below to the pockets, substantially as described.

7. In apparatus of the class described, the combination-with a suitable'stationary frame work, of an auxiliary frame work trunnioned thereon, means for adjusting the trunnioned frame work to regulate its inclination, a concentrating chute provided with pockets whose rear portions are open at the bottom for the admission of air under pressure, the said pockets being also open at the top to permit the escape of the air, the said chute being mounted on the truniiioned frame work to permit a transverse oscillation, substantially as described.

8. In dry concentrating apparatus, the combination with a suitable stationary frame work, of an auxiliary frame work trunnioned thereon, a concentrating chute provided with 9. In a dry concentrator, the combinationwith a suitable stationary frame work, of an auxiliary frame work trunnioned thereon, means for 10 cking the trunnioned frame work in the desired position of adjustment, a concentrating chute provided with an air box underneath and having pockets whose rear portions are open at the bottomfor the admission of air from the said box, the said chute and air box being suitably connected and mounted to permit an oscillatory movement in a transverse direction, substantially as described.

10. Achute for dry concentration having its bottom provided with a series of pockets having portions in the rear open for the admission of air under pressure, the air spaces of ockets whose rear portions are open from be-. ow for the admission of air under pressure,-

the various pockets varying in width for the purpose set forth.

' 11. A chute for dry concentration having its bottom provided with pockets, a plate connected with the said bottom and having passages for the admission of air under pressure to the said pockets, the said plate being provided with recesses located intermediate the pockets in the bottom of the chute and the air passages in the lower plate.

12. In a dry concentrator, the combination of a dry sluice'provided with pockets whose forward portions are closed at the bottom and whose rear portions are open at the bottom, means for introducing air under pressure to the said pockets from below, and means for imparting a vibratory motion to the chute, substantially as described.

13. Amachine of the class described, having a chute or sluice whose bottom is provided with a series of pockets whose forward portions are closed at the bottom, and whose rear portions are mesh covered and open at the bottom to permit the introduction of an air blast from below, the rear portions of the pockets being also open to permit the escape of the air.

14. A concentrating chute or sluice whose bottom is provided vith a series of pockets whose rear portions are open to permit the introduction of an air blast, the rear portions of the ockets being open to permit the escape o the air, the forward portions of the pockets being closed.

15. A dry concentrating chute or sluice whose bottom is provided with pockets whose forward portions are closed and whose rear portions are open to permit the introduction of an air blast, the rear portions of the pockets being also open to permit the escape of the air.

16. A concentrating chute or sluice having pockets whose rear portions are open at the bottom for the introduction of an air blast and at the top for the escape of the air.

17. A concentrating chute or sluice having pockets, and means for introducing air under .pressure to the rear portions of the pockets which are open at the top for the escape of the air.

In testimony whereof I affix my signature in presence of two witnesses.

HOMER P. CURTIS. 

